Use the standard reduction potentials in the table to rank species by decreasing…

CHEMISTRY · Single correct · A Level · Chemistry · Electrode potentials · Electrode potentials

Problem

Use the standard reduction potentials in the table to rank species by decreasing oxidising power. The standard reduction potentials

E^\circ

of the following systems are:

System	$E^\circ$ (volts)
(i) $\text{MnO}_4^- + 8\text{H}^+ + 5\text{e}^- \longrightarrow \text{Mn}^{2+} + 4\text{H}_2\text{O}$	1.51
(ii) $\text{Sn}^{4+} + 2\text{e}^- \longrightarrow \text{Sn}^{2+}$	0.15
(iii) $\text{Cr}_2\text{O}_7^{2-} + 14\text{H}^+ + 6\text{e}^- \longrightarrow 2\text{Cr}^{3+} + 7\text{H}_2\text{O}$	1.33
(iv) $\text{Ce}^{4+} + \text{e}^- \longrightarrow \text{Ce}^{3+}$	1.61

The oxidising power of the various species decreases in the order: (A)

\text{Ce}^{4+} > \text{Cr}_2\text{O}_7^{2-} > \text{Sn}^{4+} > \text{MnO}_4^-

(B)

\text{Ce}^{4+} > \text{MnO}_4^- > \text{Cr}_2\text{O}_7^{2-} > \text{Sn}^{4+}

(C)

\text{Cr}_2\text{O}_7^{2-} > \text{Sn}^{4+} > \text{Ce}^{4+} > \text{MnO}_4^-

(D)

\text{MnO}_4^- > \text{Ce}^{4+} > \text{Sn}^{4+} > \text{Cr}_2\text{O}_7^{2-}